Thin film transistor substrate and display panel having the same

ABSTRACT

A thin film transistor array panel device comprises: a base substrate; a barrier layer disposed over the base substrate and comprising a plurality of transparent material layers; and an array of thin film transistors disposed over the barrier layer. A difference between a refractive index of the barrier layer and a refractive index of the base substrate may be within about 6%. The transparent material layers may be arranged such that the transparent material layers having compressive residual stress and the transparent material layers having tensile residual stress are alternately stacked. Each of the transparent material layers may comprise silicon oxynitride (SiON).

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 15/045,688, filed Feb. 17, 2016, which claims priority under 35USC §119 to Korean Patent Application No. 10-2015-0061482, filed on Apr.30, 2015, in the Korean Intellectual Property Office (KIPO), thedisclosures of which are incorporated by reference herein in theirentireties.

BACKGROUND

1. Field

The present disclosure relates to a thin film transistor array panel anda display panel having the same.

2. Description of the Related Art

With development of the information-oriented society, various displaypanels such as an organic light emitting diode (OLED) display panel, aliquid crystal display (LCD) panel, an electrophoresis (EPD) panel andan electro-wetting display (EWD) panel are being used.

In recent years, display devices have become thin and light weight, andhighly mobile. Further, some display devices are even bendable orfoldable. Such display devices may use a flexible substrate whichincludes a polymer resin instead of a glass substrate.

SUMMARY

An aspect may provide a thin film transistor substrate preventingmoisture penetration and having improved light transmittance.

Another aspect may provide a display panel having the thin filmtransistor substrate.

One aspect of the invention provides a thin film transistor array paneldevice, which may comprise: a base substrate; a barrier layer disposedover the base substrate and comprising a plurality of transparentmaterial layers, each of which is substantially transparent; and anarray of thin film transistors disposed over the barrier layer, whereina difference between a refractive index of the barrier layer and arefractive index of the base substrate is within about 6%.

In the foregoing device, a difference between a refractive index of eachof the plurality of transparent material layers and the refractive indexof the base substrate may be within about 6%. The plurality oftransparent material layers may comprise first and second transparentmaterial layers immediately neighboring each other without anyintervening transparent material layer therebetween, wherein the firsttransparent material layer has compressive residual stress and thesecond transparent material layer has tensile residual stress. Thebarrier layer may comprise a multi-layered structure of the transparentmaterial layers arranged such that the transparent material layershaving compressive residual stress and the transparent material layershaving tensile residual stress are alternately stacked. The plurality oftransparent material layers may comprise an uppermost transparentmaterial layer and a lowermost transparent material layer which havecompressive residual stress.

Still in the foregoing device, the transparent material layers may beformed of the same material. Each of the transparent material layers maycomprise silicon oxynitride (SiON). The device may further comprise abuffer layer disposed between the barrier layer and the thin filmtransistors, wherein the buffer layer is formed of the same material asthat of the transparent material layers. Each thin film transistor maycomprise a semiconductor active layer, a gate electrode, a sourceelectrode and a drain electrode, wherein the thin film transistor arraypanel device further comprises a gate insulating layer disposed betweenthe semiconductor active layer and the gate electrode, wherein the gateinsulating layer is formed of the same material as that of thetransparent material layers. The device may further comprise aninterlayer insulating layer insulating the gate electrode and the sourceelectrode and the drain electrode, wherein the interlayer insulatinglayer is formed of the same material as that of the transparent materiallayers. The base substrate may comprise one of polyethersulfone (PES),polyacrylate, polyetherimide (PEI), polyethyelenen naphthalate (PEN),polyethylene terephthalate (PET), polyphenylene sulfide (PPS),polyarylate (PAR), polyimide (PI), polycarbonate (PC), triacetatecellulose (TAC) or cellulose acetate propionate (CAP). The basesubstrate may comprise fiberglass reinforced plastic (FRP).

Another aspect of the invention provides a display panel which maycomprise: the foregoing thin film transistor array panel device; and anarray of pixels disposed over the thin film transistor array paneldevice.

In the foregoing display panel, a difference between a refractive indexof each of the transparent material layers and the refractive index ofthe base substrate may be within about 6%. A first the plurality oftransparent material layers may comprise first and second transparentmaterial layers immediately neighboring each other without anyintervening transparent material layer, wherein the first transparentmaterial layer has compressive residual stress and the secondtransparent material layer has tensile residual stress. The barrierlayer may comprise a multi-layered structure of the transparent materiallayers arranged such that the transparent material layers havingcompressive residual stress and the transparent material layers havingtensile residual stress are alternately stacked. The plurality oftransparent material layers may comprise an uppermost transparentmaterial layer and a lowermost transparent material layer which havecompressive residual stress.

Still in the foregoing display panel, each of the transparent materiallayers may comprise silicon oxynitride (SiON). The thin film transistorarray panel device may further comprise a buffer layer disposed betweenthe barrier layer and the thin film transistors, wherein the bufferlayer is formed of the same material as that of the transparent materiallayers. Each thin film transistor may comprise a semiconductor activelayer, a gate electrode, a source electrode and a drain electrode,wherein the thin film transistor array panel device further comprises agate insulating layer disposed between the semiconductor active layerand the gate electrode, wherein the gate insulating layer is formed ofthe same material as that of the transparent material layers.

Yet in the foregoing display panel, the display panel may furthercomprise an interlayer insulating layer insulating the gate electrodeand the source electrode and the drain electrode, wherein the interlayerinsulating layer is formed of the same material as that of thetransparent material layers. The display panel may further comprise anencapsulating panel disposed over the thin film transistor array panelfor protecting the pixels from external substances, wherein each pixelcomprises a light emitting diode.

Still another aspect of the invention provides a thin film transistorarray panel device, which may comprise: a base substrate; a barrierlayer disposed over the base substrate and comprising a plurality oftransparent material layers, each of which is substantially transparent;and an array of thin film transistors disposed over the barrier layer,wherein the plurality of transparent material layers comprise first andsecond transparent material layers immediately neighboring each otherwithout any intervening transparent material layer therebetween, whereinthe first transparent material layer has compressive residual stress andthe second transparent material layer has tensile residual stress.

In the foregoing device, the barrier layer may comprise a multi-layeredstructure of the transparent material layers arranged such that thetransparent material layers having compressive residual stress and thetransparent material layers having tensile residual stress arealternately stacked. The plurality of transparent material layers maycomprise an uppermost transparent material layer and a lowermosttransparent material layer which have compressive residual stress. Eachof the transparent material layers may comprise silicon oxynitride(SiON). The device may further comprise a buffer layer disposed betweenthe barrier layer and the thin film transistors, wherein the bufferlayer is formed of the same material as that of the transparent materiallayers.

Still in the foregoing device, each thin film transistor may comprise asemiconductor active layer, a gate electrode, a source electrode and adrain electrode, wherein the thin film transistor array panel devicefurther comprises a gate insulating layer disposed between thesemiconductor active layer and the gate electrode, wherein the gateinsulating layer is formed of the same material as that of thetransparent material layers. The device may further comprise aninterlayer insulating layer insulating the gate electrode and the sourceelectrode and the drain electrode, wherein the interlayer insulatinglayer is formed of the same material as that of the transparent materiallayers. A difference between a refractive index of the transparentmaterial layers and a refractive index of the base substrate may bewithin about 6%, wherein the thin film transistor array panel device isflexible.

Yet another aspect of the invention provides a display panel, which maycomprise: the foregoing thin film transistor array panel device; and anarray of pixels disposed over the thin film transistor array paneldevice.

In the foregoing display panel, the barrier layer may comprise amulti-layered structure of the transparent material layers arranged suchthat the transparent material layers having compressive residual stressand the transparent material layers having tensile residual stress arealternately stacked. The plurality of transparent material layers maycomprise an uppermost transparent material layer and a lowermosttransparent material layer which have compressive residual stress. Eachof the transparent material layers may comprise silicon oxynitride(SiON), wherein the thin film transistor array panel device is flexible.The thin film transistor array panel device may further comprise abuffer layer disposed between the barrier layer and the thin filmtransistors, wherein the buffer layer is formed of the same material asthat of the transparent material layers. Each thin film transistor maycomprise a semiconductor active layer, a gate electrode, a sourceelectrode and a drain electrode, wherein the thin film transistor arraypanel device further comprises a gate insulating layer disposed betweenthe semiconductor active layer and the gate electrode, wherein the gateinsulating layer is formed of the same material as that of thetransparent material layers. The thin film transistor array panel devicemay further comprise an interlayer insulating layer insulating the gateelectrode and the source electrode and the drain electrode, wherein theinterlayer insulating layer is formed of the same material as that ofthe transparent material layers.

Still in the foregoing display panel, a difference between a refractiveindex of the transparent material layers and the refractive index of thebase substrate may be within about 6%. The display panel may furthercomprise an encapsulating panel disposed over the thin film transistorarray panel for protecting the pixels from external substances, whereineach pixel comprises a light emitting diode.

A further aspect of the invention provides a thin film transistor arraypanel device, which may comprise: a base substrate; a barrier layerdisposed over the base substrate and comprising a plurality oftransparent material layers, each of which is substantially transparentand comprises silicon oxynitride (SiON); and an array of thin filmtransistors disposed over the barrier layer.

In the foregoing device, the plurality of transparent material layersmay comprise first and second transparent material layers immediatelyneighboring each other without any intervening transparent materiallayer therebetween, wherein the first transparent material layer hascompressive residual stress and the second transparent material layerhas tensile residual stress. The barrier layer may comprise amulti-layered structure of the transparent material layers arranged suchthat the transparent material layers having compressive residual stressand the transparent material layers having tensile residual stress arealternately stacked. The plurality of transparent material layers maycomprise an uppermost transparent material layer and lowermosttransparent material layer which have compressive residual stress. Thedevice may further comprise a buffer layer disposed between the barrierlayer and the thin film transistors, wherein the buffer layer comprisessilicon oxynitride (SiON).

Still in the foregoing device, each thin film transistor may comprise asemiconductor active layer, a gate electrode, a source electrode and adrain electrode, wherein the thin film transistor array panel devicefurther comprises a gate insulating layer disposed between thesemiconductor active layer and the gate electrode, wherein the gateinsulating layer comprises silicon oxynitride (SiON). The device mayfurther comprise an interlayer insulating layer insulating the gateelectrode and the source electrode and the drain electrode, wherein theinterlayer insulating layer comprises silicon oxynitride (SiON). Adifference between a refractive index of the transparent material layersand a refractive index of the base substrate may be within about 6%.

Still a further aspect of the invention provides a display panel, whichmay comprise: the foregoing thin film transistor array panel device; andan array of pixels disposed over the thin film transistor array panel.

In the foregoing display panel, the plurality of transparent materiallayers may comprise first and second transparent material layersimmediately neighboring each other without any intervening transparentmaterial layer therebetween, wherein the first transparent materiallayer has compressive residual stress and the second transparentmaterial layer has tensile residual stress. The barrier layer maycomprise a multi-layered structure of the transparent material layersarranged such that the transparent material layers having compressiveresidual stress and the transparent material layers having tensileresidual stress are alternately stacked. The plurality of transparentmaterial layers may comprise an uppermost transparent material layer anda lowermost transparent material layer which have compressive residualstress.

Yet in the display panel, the thin film transistor array panel devicemay further comprise a buffer layer disposed between the barrier layerand the thin film transistors, wherein the buffer layer comprisessilicon oxynitride (SiON). Each thin film transistor comprises asemiconductor active layer, a gate electrode, a source electrode and adrain electrode, wherein the thin film transistor array panel devicefurther comprises a gate insulating layer disposed between thesemiconductor active layer and the gate electrode, wherein the gateinsulating layer comprises silicon oxynitride (SiON). The thin filmtransistor array panel device may further comprise an interlayerinsulating layer insulating the gate electrode and the source electrodeand the drain electrode, wherein the interlayer insulating layercomprises silicon oxynitride (SiON). A difference between a refractiveindex of the transparent material layers and a refractive index of thebase substrate may be within about 5.5%.

In an embodiment, a thin film transistor substrate may include a basesubstrate, a barrier layer disposed on the base substrate and includinga plurality of transparent material layer and a thin film transistordisposed on the barrier layer. The difference between a refractive indexof the barrier layer and a refractive index of the base substrate may bewithin 6%.

The difference between a refractive index of the plurality oftransparent material layers and the refractive index of the basesubstrate may be within 6%.

One of the transparent material layers adjacent to each other may havecompressive stress and other one may have tensile stress. The barrierlayer may include the transparent material layers having compressivestress and the transparent material layers having tensile stress,alternately stacked. The uppermost transparent material layer and thelowermost transparent material layer may have compressive stress.

The thin film transistor substrate may further include a buffer layerdisposed between the barrier layer and the thin film transistor. Thebuffer layer may include a same material as the transparent materiallayers.

The thin film transistor may include a semiconductor active layer, agate electrode, a gate insulating layer disposed between thesemiconductor active layer and the gate electrode, a source electrodeand a drain electrode. The gate insulating layer may include a samematerial as the transparent material layers.

The thin film transistor substrate may further include an interlayerinsulating layer insulating the gate electrode and the source electrodeand the drain electrode. The interlayer insulating layer may include asame material as the transparent material layers.

The transparent material layers may include the same material. Thetransparent material layers may include silicon oxynitride (SiON).

The base substrate may include one of polyethersulfone (PES),polyacrylate, polyetherimide (PEI), polyethyelenen naphthalate (PEN),polyethylene terephthalate (PET), polyphenylene sulfide (PPS),polyarylate (PAR), polyimide (PI), polycarbonate (PC), triacetatecellulose (TAC) or cellulose acetate propionate (CAP). The basesubstrate may include fiber glass reinforced plastic (FRP).

In an embodiment, a thin film transistor substrate may include a basesubstrate, a barrier layer disposed on the base substrate and includinga plurality of transparent material layer and a thin film transistordisposed on the barrier layer. Remaining stress of the transparentmaterial layers that are adjacent to each other may have differentstress properties.

In an embodiment, a thin film transistor substrate may include a basesubstrate, a barrier layer disposed on the base substrate and includinga plurality of transparent material layers including silicon oxynitride(SiON) and a thin film transistor disposed on the barrier layer.

In an embodiment, a display panel may include the thin film transistorsubstrate and an emitting device disposed on the thin film transistorsubstrate.

An encapsulating member that isolates the emitting device from anexternal environment may be further included. The encapsulating membermay be an opposed substrate facing the thin film transistor substrate.

The display panel may include a barrier layer disposed on a basesubstrate, thereby preventing moisture from penetrating into a displaydevice.

Since the difference between the refractive index of the barrier layerand the refractive index of the base substrate is small, the light maybe prevented from being reflected at an interface between the barrierlayer and the base substrate. Accordingly, the light transmittance ofthe display panel may be improved.

As for the barrier layer, a plurality of transparent material layers maybe stacked, and one of the transparent material layers adjacent to eachother may have compressive stress while other one may have tensilestress. Accordingly, residual stress inside the barrier layer may berelieved. Therefore, the stress which is applied to the base substrateby the barrier layer may be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described more fully hereinafter with referenceto the accompanying drawings; however, they may be embodied in differentforms and should not be construed as limited to the embodiments setforth herein. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the embodiments to those skilled in the art.

In the drawing figures, dimensions may be exaggerated for clarity ofillustration. It will be understood that when an element is referred toas being “between” two elements, it can be the only element between thetwo elements, or one or more intervening elements may also be present.Like reference numerals refer to like elements throughout.

FIG. 1 is an exploded perspective view for explaining a display devicein accordance with an embodiment.

FIG. 2 is a cross-sectional view of the display device shown in FIG. 1.

FIG. 3 is a cross-sectional view for explaining the display device shownin FIG. 1.

FIG. 4 is an expanded view of an area EA shown in FIG. 3.

FIGS. 5 to 9 are process cross-sectional views for explaining a methodof manufacturing the display panel shown in FIGS. 1 to 4.

FIG. 10 is a graph for explaining a change in a refractive index of atransparent material layer in accordance with an applied power.

FIG. 11 is a graph for explaining a change in a refractive index of atransparent material layer in accordance with a flow ratio of an ammoniagas and a nitrous oxide gas.

FIGS. 12 to 14 are simulation graphs for explaining a lighttransmittance in accordance with a structure of a barrier layer disposedon a base substrate.

DETAILED DESCRIPTION

In the following detailed description, only some embodiments of thepresent invention have been shown and described, simply by way ofillustration. As those skilled in the art would realize, the describedembodiments may be modified in various different ways, all withoutdeparting from the spirit or scope of the present invention.Accordingly, the drawings and description are to be regarded asillustrative in nature and not restrictive. In addition, it will beunderstood that when an element or layer is referred to as being “on”,“connected to” or “coupled to” another element or layer, it can bedirectly on, connected or coupled to the other element or layer orintervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. Like numbers refer to likeelements throughout. As used herein, the term “and/or” includes any andall combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one element, component, region, layer or section fromanother region, layer or section. Thus, a first element, component,region, layer or section discussed below could be termed a secondelement, component, region, layer or section without departing from theteachings of the present invention.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to limit the invention thereto. Asused herein, the singular forms, “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “includes”and/or “including”, when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

FIG. 1 is an exploded perspective view for explaining a display devicein accordance with an embodiment. FIG. 2 is a cross-sectional view ofthe display device shown in FIG. 1.

Referring to FIGS. 1 and 2, a display device may include a display panel100, a housing 200 and a driving circuit part 300.

In embodiments, the display panel 100 may be flexible. The display panel100 may be substantially transparent such that a substantial amountlight beams passes therethrough. In addition, the display panel 100 mayinclude a display area DA for displaying images and a non-display areaat a periphery of the display area DA.

However, the display panel 100 is not limited thereto. For example, butwithout limitation thereto, a self light emission type display panelsuch as an organic light emitting display (OLED) panel may be used forthe display panel 100. In addition, a nonemissive display panel such asa liquid crystal display (LCD) panel, an electro-phoretic display (EPD)panel, and an electro-wetting display (EWD) panel may be used for thedisplay panel 100. If a nonemissive display panel is used for thedisplay panel 100, a mobile device employing the display panel mayinclude a back-light unit for supplying light to the display panel 100.In an embodiment, the organic light emitting display panel is describedas an example of the display panel 100.

The display area DA may include a plurality of pixel areas. Lightsemitted from the pixel areas may have different colors. For example, butwithout limitation thereto, light emitted from the pixel areas may haveone of the following colors: red; green; blue; cyan; magenta; or yellow.

The display panel 100 may include a thin film transistor substrate 110which may be referred to as a thin-film transistor array panel, adisplay device disposed in each of the pixel areas on the thin filmtransistor substrate 110 and a sealing member 120 that can be referredas a encapsulation panel separating or isolating the display device froman external environment. The display devices may be disposed in each ofthe pixel areas. In embodiments, for providing a flexible display, thethin film transistor array panel 110 and the encapsulation panel 120 areflexible.

In each of the pixel areas, the thin film transistor substrate 110 mayinclude a base substrate and at least one thin film transistor disposedon the base substrate. In embodiments, an array of thin film transistorsis formed over the base substrate.

In embodiments, the display device may be an organic light emittingdevice. For example, but without limitation thereto, the display devicemay include a first electrode coupling to the thin film transistor, anorganic layer disposed on the first electrode and a second electrodedisposed on the organic layer. One of the first electrode and the secondelectrode may be an anode electrode, and the other may be a cathodeelectrode. At least one of the first electrode and the second electrodemay be a transmissive electrode. For example, but without limitationthereto, if the display device is an organic light emitting device of abottom emission type, the first electrode may be a transmissiveelectrode, and the second electrode may be a reflective electrode. Ifthe display device is an organic light emitting device of a top emissiontype, the first electrode may be a reflective electrode, and the secondelectrode may be a transmissive electrode. If the display device is anorganic light emitting device of a both top and bottom emission type,the first electrode and the second electrode may be transmissiveelectrodes.

The organic layer may include at least an emitting layer (EML).Generally, the organic layer may have a multi-layered thin filmstructure. The color of the light from the emitting layer may be one ofred, green, blue or white. However, it is not limited thereto. Forexample, but without limitation thereto, the color of the light from theemitting layer may be one of magenta, cyan, or yellow.

The sealing member 120 may isolate the display device from the externalenvironment. The sealing member 120 may be a sealing substrate facingthe thin film transistor substrate 110. The sealing member 120 may,through a sealant, be attached to the thin film transistor substrate110. The sealant may be disposed in the non-display area NDA.

The sealing member 120 may be a sealing layer including a plurality ofinorganic layers and a plurality of organic layers covering the displaydevice OLED. The sealing layer may prevent penetration of moisture andoxygen into the display device OLED on the second electrode E2.

An area of the sealing member 120 may be smaller than or substantiallythe same as that of the thin film transistor substrate 110. For example,but without limitation thereto, the sealing member 120 may over thedisplay area DA of the thin film transistor substrate 110 and expose apart of the non-display area NDA.

The housing 200 may include a material having an elastic or flexibleproperty. The housing 200 may accommodate at least a part of the displaypanel 100 and the driving circuit part 300.

The driving circuit part 300 may be disposed between the display panel100 and the housing 200. The driving circuit part 300 may include adriving IC, a coupling film and a circuit board.

The driving IC may include a gate driving IC and a data driving IC for adriving chip for driving the display panel 100.

The coupling film may include a plurality of wires formed on afilm-typed substrate. The coupling film may mount the driving IC with atape carrier package (TCP) or a chip on film (COF) to be electricallycoupled to the thin film transistor substrate 110.

The circuit board may be electrically coupled to the thin filmtransistor substrate 110 via the coupling film and may supply a gatesignal and a data signal to the thin film transistor substrate 110. Thecircuit board may be a printed circuit board (CPB) or a flexible printedcircuit board (FPCB). Various electronic devices including a power unitand a controller may be mounted on the circuit board.

FIG. 3 is a cross-sectional view for explaining the display device shownin FIG. 1. FIG. 4 is an expanded view of an area EA shown in FIG. 3.

Referring to FIGS. 1 to 4, in embodiments, a display panel 100 mayinclude a thin film transistor substrate 110, a display device OLEDwhich is an organic light emitting diode and disposed on the thin filmtransistor substrate 110 and a sealing member 120 isolating the displaydevice OLED from an external environment.

The thin film transistor substrate 110 may include a base substrate SUBand at least one thin film transistor disposed on the base substrateSUB.

The base substrate SUB may be a flexible substrate. The base substrateSUB may be one of film base substrate and plastic base substrateincluding high molecular organic matters. For example, but withoutlimitation thereto, the base substrate SUB may include one ofpolyethersulfone (PES), polyacrylate, polyetherimide (PEI),polyethyelenen naphthalate (PEN), polyethylene terephthalate (PET),polyphenylene sulfide (PPS), polyarylate (PAR), polyimide (PI),polycarbonate (PC), triacetate cellulose (TAC) or cellulose acetatepropionate (CAP). The base substrate SUB may include fiber glassreinforced plastic (FRP).

In embodiments, a material used for the base substrate SUB may haveresistance (thermal resistance) to high processing temperature during aprocess of manufacturing the display panel 100.

A barrier layer BAL may be disposed between the base substrate SUB andthe thin film transistor. In embodiments, the barrier layer BAL contactsthe base substrate. Here, a difference between a refractive index of thebarrier layer BAL and a refractive index of the base substrate SUB maybe about 6% or less. If the difference between the refractive index ofthe barrier layer BAL and the refractive index of the base substrate SUBis less than about 6%, reflectivity of light on an interface of thebarrier layer BAL and the base substrate SUB may be sufficiently smallto minimize or avoid deterioration of the light transmittance of thethin film transistor substrate 110. In embodiments, the differencebetween the refractive index of the barrier layer BAL and the refractiveindex of the base substrate SUB may be about 1%, about 1.3%, about 1.6%,about 1.9%, about 2%, about 2.3%, about 2.5%, about 2.7%, about 3%,about 3.2%, about 3.5%, about 3.8%, about 4.2%, about 4.7%, about 5.1%,about 5.5%, about 5.8%, about 6% or about 6.5%. In an embodiment, thedifference between the refractive index of the barrier layer BAL and therefractive index of the base substrate SUB is a number within anumerical range between two selected from the afore-mentioned numbers.For example, the difference may be about 4.5%.

In embodiments, the barrier layer BAL is formed to inhibit moisture andoxygen from penetrating into the display panel to reach thesemiconductor active layer SA of the thin film transistor. Further, thebarrier layer may inhibit impurities from being diffused from the basesubstrate SUB so as to minimize the dispersion of the impurities to thesemiconductor active layer SA. To this end, in embodiments, the barrierlayer may be formed a material having characteristics of blockingmoisture, oxygen and/or doping impurities. Further, the barrier layermay be formed to have a thickness sufficient to block the moisture,oxygen and/or doping impurities.

The barrier layer BAL may have a structure of a plurality of transparentactive layers BAL1, BAL2, BAL3, BAL4 and BAL5. The refractive index ofthe transparent material layers BAL1, BAL2, BAL3, BAL4 and BAL5 and therefractive index of the base substrate SUB may be substantially thesame. Also, the difference between the refractive index of thetransparent material layers BAL1, BAL2, BAL3, BAL4 and BAL5 may be about6% or less. For example, but without limitation thereto, the transparentmaterial layers BAL1, BAL2, BAL3, BAL4 and BAL5 may include the samematerials, and the refractive index of the transparent material layersBAL1, BAL2, BAL3, BAL4 and BAL5 may be substantially the same. Inembodiments, two immediately neighboring layers among the plurality oftransparent material layers contact each other, and no intervening layeror portion is provided therebetween.

Residual stress of one of the transparent material layers BAL1, BAL2,BAL3, BAL4 and BAL5 is different from that of immediately neighboringone of another the transparent material layers BAL1, BAL2, BAL3, BAL4and BAL5. For example, the transparent material layer BAL2 has tensileresidual stress while the transparent material layers BAL1 and BAL3 havecompressive residual stress. In embodiments, the number of thetransparent material layers BAL1, BAL2, BAL3, BAL4 and BAL5 may be anodd number. Also, in embodiments, the residual stress of the uppermosttransparent material layer and the lowermost transparent material layermay be compressive residual stress, but not limited thereto.

For example, in embodiments illustrated in FIG. 4, the barrier layer BALmay include first to fifth transparent material layers BAL1, BAL2, BAL3,BAL4 and BAL5.

The residual stress of the first transparent material layer BAL1, thethird transparent material layer BAL3 and the fifth transparent materiallayer BAL5 may have the same residual stress properties. For example,but without limitation thereto, the first transparent material layerBAL1, the third transparent material layer BAL3, and the fifthtransparent material layer BAL5 may be compressive residual stress.

The residual stress of the second transparent material layer BAL2 andthe fourth transparent material layer BAL4 may have the same residualstress properties. For example, but without limitation thereto, theresidual stress of the second transparent material layer BAL2 and thefourth transparent material layer BAL4 may be tensile residual stress.

In the barrier layer BAL, since transparent material layers BAL1, BAL2,BAL3, BAL4 and BAL5 which have different residual stress properties arealternately stacked, the residual stress between the transparentmaterial layers BAL1, BAL2, BAL3, BAL4 and BAL5 may be relaxed.Accordingly, compared to the barrier layer BAL of a single layerstructure, the barrier layer BAL may maintain a state in which theresidual stress is relaxed.

In addition, compared to the barrier layer of the single layerstructure, the barrier layer BAL may include the plurality oftransparent material layers BAL1, BA2, BAL3, BAL4 and BAL5. Therefore,the barrier layer BAL may reduce penetration of moisture and impuritiesoccurring due to pin-hole effect.

The transparent material layers BAL1, BAL2, BAL3, BAL4 and BAL5 mayinclude one of silicon oxide (SiOx), silicon nitride (SiNx) or siliconoxynitride (SiON). For example, but without limitation thereto, thetransparent material layers BAL1, BAL2, BAL3, BAL4 and BAL5 may includesilicon oxynitride (SiON). The silicon oxynitride may easily control therefractive index depending on content of oxygen and nitrogen. If thecontent of nitrogen increases, the refractive index of the siliconoxynitride may increase. Furthermore, if the content of oxygenincreases, the refractive index of the silicon oxynitride may decrease.

A buffer layer BUL may be disposed between the thin film transistorarray and the barrier layer BAL. In embodiments, the buffer layer BULcontacts the layer BAL5 of the barrier layer. The buffer layer BUL mayinclude a material that is the same as the transparent material layersBAL1, BAL2, BAL3, BAL4 and BAL5, for example, but without limitationthereto, silicon oxynitride (SiON). In embodiments, the buffer layer BULmay have substantially the same refractive index as the transparentmaterial layers BAL1, BAL2, BAL3, BAL4 and BAL5. Therefore, thereflection of the light at an interface between the buffer layer BUL andthe fifth transparent material layer BAL5 may be minimized or reduced asthe difference in the refractive index of the buffer layer BUL and thefifth transparent material BAL5 is sufficiently small or there is nosubstantial difference of the refractive index between the layers BULand BAL5.

The thin film transistor may be disposed on the buffer layer BUL. Thethin film transistor may include the semiconductor active layer SA, agate electrode GE, a source electrode SE and a drain electrode DE.

The semiconductor active layer SA may be disposed on the buffer layerBL. The semiconductor active layer SA may include one of amorphoussilicon (a-Si), polycrystalline silicon (p-Si) or oxide semiconductor.An area in contact with the source electrode SE and the drain electrodeDE in the semiconductor active layer SA may be a source area and a drainarea into which impurities are doped or injected. An area between thesource area and the drain area may be a channel area. The oxidesemiconductor may include at least one of Zn, In, Ga, Sn or any mixturethereof. For example, but without limitation thereto, the oxidesemiconductor may include indium-gallium-zinc oxide (IGZO).

In embodiments, if the semiconductor active layer SA includes an oxidesemiconductor, a light blocking layer may be disposed at an upperportion or a lower portion of the semiconductor active layer SA to blocklight flowing into the semiconductor active layer SA.

A gate insulating layer GI may be disposed on the semiconductor activelayer SA. The gate insulating layer GI may cover the semiconductoractive layer SA and insulate the semiconductor active layer SA and thegate electrode GE. The gate insulating layer GI may include at least onesilicon oxynitride (SiON). For example, but without limitation thereto,the gate insulating layer GI may include a material that is the same asthe first to fifth transparent material layers BAL1, BAL2, BAL3, BAL4and BAL5, for example, but without limitation thereto, siliconoxynitride (SiON). The gate insulating layer GI may have substantiallythe same refractive index as the buffer layer BUL. Accordingly, thelight may be prevented from being reflected from an interface betweenthe gate insulating layer GI and the buffer layer BUL due to thedifference in refractive index of the gate insulating layer GI and thebuffer layer BUL.

The gate insulating layer GI may include a first layer which includessilicon oxide (SiOX) disposed on the semiconductor layer SA and a secondlayer disposed on the first layer and which includes silicon oxynitride.The first layer which includes the silicon oxide may have superioradhesive strength with the semiconductor active layer SA. Also,interface stability of the first layer and the semiconductor activelayer SA may be superior.

The gate electrode GE may be disposed on the gate insulating layer GI.The gate electrode GE may be disposed overlapping the semiconductoractive layer SA. The gate electrode GE may include at least one ofaluminum (Al), aluminum alloy (Al alloy), silver (Ag), tungsten (W),copper (Cu), nickel (Ni), chrome (Cr), molybdenum (Mo), titanium (Ti),platinum (Pt), tantalum (Ta), neodymium (Nd), scandium (Sc) or any alloythereof.

An interlayer insulating layer ILD may be disposed on the gate electrodeGE. The interlayer insulating layer ILD may insulate the gate electrodeGE and the source electrode and the drain electrode DE. The interlayerinsulating layer ILD may include the material that is the same as thefirst to fifth transparent material layers BAL1, BAL2, BAL3, BAL4 andBAL5, for example, but without limitation thereto, silicon oxynitride(SiON). In embodiments, the interlayer insulating layer ILD may havesubstantially the same refractive index as the gate insulating layer GI.Accordingly, the light may be prevented from being reflected from theinterface between the interlayer insulating layer ILD and the gateinsulating layer GI due to the difference in the refractive index of theinterlayer insulating layer ILD and the gate insulating layer GI.

The source electrode SE and the drain electrode DE may be disposed onthe interlayer insulating layer ILD. The source electrode SE and thedrain electrode DE may be insulated from the gate electrode GE due tothe interlayer insulating layer ILD. The source electrode SE and thedrain electrode DE may contact the source area and the drain area.

In an embodiment, an example of the thin film transistor of a top gatestructure is given. However, it should not be limited thereto. Forexample, but without limitation thereto, the thin film transistor may bea thin film transistor having a bottom gate structure.

A protective layer PSV may be disposed on the base substrate SUB wherethe thin film transistor is disposed. A part of the protective layer PSVmay be removed and expose a part of the drain electrode DE. Theprotective layer PSV may include at least one layer. For example, butwithout limitation thereto, the protective layer PSV may be an organicprotective layer. The organic protective layer PSV may include one ofacryl, polyimide (PI), polyamide (PA), or benzocyclobutene (BCB). Theorganic protective layer may be transparent and have fluidity and it maybe a planarizing layer capable of flattening by alleviating a bend or acurve of a structure of a lower portion.

The protective layer PSV may include an inorganic protective layer andan organic protective layer disposed on the inorganic protective layer.The inorganic protective layer may include the material that is the sameas the first to fifth transparent material layers BAL1, BAL2, BAL3, BAL4and BAL5, for example, but without limitation, silicon oxynitride(SiON). In embodiments, the inorganic protective layer may havesubstantially the same refractive index as the interlayer insulatinglayer ILD. Accordingly, the light may be prevented from being reflectedfrom the interface between the inorganic protective layer and theinterlayer insulating layer ILD due to the difference in the refractiveindex of the inorganic protective layer and the interlayer insulatinglayer ILD. In embodiments, all the transparent material layers of thebarrier layer, the gate insulation layer, the interlayer insulationlayer and the protective layer may be formed of the same material, forexample, silicon oxide (SiOx), silicon nitride (SiNx) or siliconoxynitride (SiON), and may have substantially the same refractive index.

The display device OLED that contacts the drain electrode DE of the thinfilm transistor may be disposed on the protective layer PSV. The displaydevice OLED may be an organic light emitting device. Depending on theemission form, the display device OLED may be one of an organic lightemitting device of a bottom emission type, an organic light emittingdevice of a top emission type or an organic light emitting device ofboth sided emission type. In an embodiment, an example of the displaydevice OLED being an organic light emitting device of a bottom type isprovided.

The display device OLED may include a first electrode E1 which is atransmissive electrode capable of allowing light to pass through, anorganic layer OL disposed on the first electrode E1 and a secondelectrode E2 which is a reflective electrode disposed on the organiclayer OL and capable of reflecting light.

The first electrode E1 may come in contact with the drain electrode DE.The first electrode E1 may be a conductive layer including a transparentconductive oxide of one of indium tin oxide (ITO), indium zinc oxide(IZO), aluminum zinc oxide (AZO), gallium doped zinc oxide (GZO), zinctin oxide (ZTO), gallium tin oxide (GTO) or fluorine doped tin oxide(FTO).

A pixel defining layer PDL may be disposed on the first electrode E1.The pixel defining layer PDL may be open, and the open area may exposethe first electrode E1, especially a part of the transparent conductivelayer E12.

The pixel defining layer PDL may include an organic insulating material.For example, but without limitation thereto, the pixel defining layerPDL may include at least one of polystylene, poly(methyl methacrylate)(PMMA), polyacrylonitrile (PAN), polyamide, polyimide, polyarylether,heterocyclic polymer, parylene, fluorinated polymer, epoxy resin,benzocyclobutene series resin, siloxane series resin or silane resin.

An organic layer OL may be disposed on the first electrode E1 which isexposed by the pixel defining layer PDL. The organic layer OL mayinclude at least an emitting layer EML and generally have a multi-layerthin film structure. For example, but without limitation thereto, theorganic layer OL may include a hole injection layer HIL injecting holes,a hole transport layer HTL having superior transportation of holes andincreasing an opportunity to re-couple holes and electrons bysuppressing movement of electrons that were not coupled in the emittinglayer EML, the emitting layer EML emitting light due to re-coupling ofthe injected electrons and holes, a hole blocking layer HBL suppressingmovement of hoes that were not coupled in the emitting layer EML, anelectron transport layer ETL smoothly transporting electrons to theemitting layer EML and an electron injection layer EIL injectingelectrons. The color of the light generated from the emitting layer maybe one of red, green, blue or white, but it is not limited thereto. Forexample, but without limitation thereto, the color of the lightgenerated from the emitting layer of the organic layer OL may be one ofmagenta, cyan or yellow.

The second electrode E2 may be disposed on the organic layer OL. Thesecond electrode E2 may include a material having a lower work functionthan the first electrode E1, for example, but without limitationthereto, at least one of molybdenum (Mo), tungsten (W), silver (Ag),magnesium (Mg), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au),nickel (Ni), neodymium (Nd), iridium (Jr), chrome (Cr), lithium (Li),calcium (Ca) or any alloy thereof. A conductive layer for preventingIR-drop of the second electrode E2 may be further included on the secondelectrode E2.

The sealing member 120 may be a sealing substrate facing the thin filmtransistor substrate 110. The sealing member 120 may include a samematerial as the base substrate SUB. The sealing member 120 may be aflexible substrate.

The sealing member 120 may isolate the display device OLED from theexternal environment and may be attached to the thin film transistorsubstrate 110 through a sealant. The sealant may be disposed in thenon-display area NDA.

The sealing member 120 may be a sealing layer including a plurality ofinorganic layers and a plurality of organic layers covering the displaydevice OLED. The sealing layer may prevent penetration of moisture andoxygen into the display device OLED on the second electrode E2. Theorganic layer may include at least one of epoxy, polyimide, polyethyleneterephthalate, polycarbonate, polyethylene or polyacrylate. Theinorganic layer may include at least one of silicon oxide (SiOx),silicon nitride (SiNx), silicon oxynitride (SiON), aluminum oxide(Al₂O₃), titanium oxide (TiO₂), zirconium oxide (ZrOx) or zinc oxide(ZnO).

An area of the sealing member 120 may be smaller than or the same as anarea of the thin film transistor 110. For example, but withoutlimitation thereto, the sealing member 120 may cover the display area DAof the thin film transistor substrate 110 and expose a part of thenon-display area NDA.

The display panel 100 may further include a filler filling a spacebetween the thin film transistor substrate 110 and the sealing member120. The filler may prevent damage to the display device OLED from anexternal impact.

The filler may include a material that is liquid or gel-like, which iscolorless, capable of allowing light to pass through. For example, butwithout limitation thereto, as a gel-like material, the filler mayinclude at least one of bisphenol A-type epoxy, cycloaliphatic epoxyresin, phenyl silicon resin or rubber, acrylic epoxy resin, or aliphaticurethane acrylate. Also, for a liquid material, the filler may includeat least one of hexamethyldisiloxane, octamethyltrisiloxane,decamethyltetrasiloxane, or dodecamethylpentasiloxane,polydimethylsiloxanes.

Also, the filler may further include a moisture absorption materialcapable of absorbing moisture. Accordingly, the filler may preventmoisture which passed through the sealing member 120 from penetratinginto the display device OLED.

The refractive index of the barrier layer BAL the refractive index ofthe buffer layer BUL, the refractive index of the gate insulating layerGI, and the refractive index of the interlayer insulating layer may bedifferent from the refractive index of the base substrate SUB withinabout 6%. Therefore, the display device may prevent the light which isemitted from the display device OLED from being lost or reduce the lossof the light as a result of total reflection and side reflection due tothe difference in interlayer refractive index. Therefore, lightextraction efficiency of the display device may increase.

In the barrier layer BAL, the transparent material layers BAL1, BAL2,BAL3, BAL4 and BAL5 having different stress properties in which residualstress is different from each other may be alternately stacked.Therefore, residual stress acting on interactions between thetransparent material layers BAL1, BAL2, BAL3, BAL4 and BAL5 may berelieved. In embodiments, the stress that is applied to the basesubstrate SUB due to the barrier layer BAL may be reduced. Accordingly,for the display device including the barrier layer BAL, there may bereduced concern for crack which may occur due to residual stress of thebarrier layer BAL.

FIGS. 5 to 9 are process cross-sectional views for explaining a methodof manufacturing the display panel shown in FIGS. 1 to 4. FIG. 10 is agraph for explaining a change in a refractive index of a transparentmaterial layer in accordance with an applied power. FIG. 11 is a graphfor explaining a change in a refractive index of a transparent materiallayer in accordance with a flow ratio of an ammonia gas and a nitrousoxide gas.

Referring to FIG. 5, a base substrate SUB may be formed on a carriersubstrate CS.

The carrier substrate CS may be a glass substrate. The carrier substrateCS may be non-flexible. In embodiments, the carrier substrate CS may bea substrate of rigid type. The carrier substrate CS may, in a subsequentprocess, support the base substrate SUB and prevent deformation of thebase substrate SUB from occurring.

The base substrate SUB may be formed by coating high molecular organicmatters on the carrier substrate CS. The high molecular organic mattersmay be one of polyethersulfone (PES), polyacrylate, polyetherimide(PEI), polyethyelenen naphthalate, polyethylene terephthalate (PET),polyphenylene sulfide (PPS), polyallylate (PAR), polyimide (PI),polycarbonate (PC), triacetate cellulose (TAC) or cellulose acetatepropionate.

After the base substrate SUB is formed, a barrier layer BAL may beformed on the base substrate SUB. The barrier layer BAL may include aplurality of transparent material layers BAL1, BAL2, BAL3, BAL4 andBAL5. For example, but without limitation, the barrier layer BAL mayinclude first to fifth transparent material layers BAL1, BAL2, BAL3,BAL4 and BAL5.

The barrier layer BAL may be formed as below.

The first transparent material layer BAL1 may be formed on the basesubstrate SUB. The residual stress of the first transparent materiallayer BAL1 may be compressive residual stress. The refractive index ofthe first transparent material layer BAL1 and the refractive index ofthe base substrate SUB may be different from each other within about 6%.

The first transparent material layer BAL1 may include at least one ofsilicon oxide (SiOX), silicon nitride (SiNx) or silicon oxynitirde(SiON). In an embodiment, an example may be provided in which the firsttransparent material layer BAL1 includes silicon oxynitride (SiON).

The first transparent material layer BAL1 may be formed through a plasmaenhanced chemical vapor deposition (PECVD) process which uses silane(SiH4) gas, ammonia (NH3) gas, and nitrous oxide (N2O) gas as processgas. By adjusting strength of the power applied in the PECVD process,the refractive index of the first transparent material layer BAL1 may becontrolled. As shown in FIG. 10, depending on the strength of the powerapplied in the PECVD process, the refractive index of the firsttransparent material layer BAL1 may change. Accordingly, it may bepossible to control the first transparent material layer BAL1 to besubstantially the same as the refractive index of the base substrateSUB.

After the first transparent material layer BAL1 is formed, a secondtransparent material layer BAL2 may be formed on the first transparentmaterial layer BALL The second transparent material layer BAL2 mayinclude a material that is the same as the first transparent materiallayer BAL1. A refractive index of the second transparent material layerBAL2 and the refractive index of the first transparent material layerBAL1 may substantially be the same. The residual stress of the secondtransparent material layer BAL2 may be tensile residual stress.

Under the PECVD condition of the first transparent material layer BAL1,the second transparent material layer BAL2 may be formed by increasingthe strength of the power being applied, reducing the flow of theammonia gas, and increasing the flow of the silane gas. Here, byadjusting the content ratio of oxygen and nitrogen included in thesilicon oxynitride, the refractive index of the second transparentmaterial layer BAL2 may be controlled. As shown in FIG. 11, based on theflow ratio of the ammonia gas and the nitrous oxide gas, the refractiveindex of the second transparent material layer BAL2 may change.Accordingly, it may be possible to adjust the refractive index of thesecond transparent material layer BAL2 to be substantially the same asthe refractive index of the base substrate SUB and he first transparentmaterial layer BAL1.

After the second transparent material layer BAL2 is formed, a thirdtransparent material layer BAL3 may be formed on the second transparentmaterial layer BAL2. The third transparent material layer BAL3 mayinclude a material that is the same as the first transparent materiallayer BAL1 and the second transparent material layer BAL2. Therefore, arefractive index of the third transparent material layer BAL3 and therefractive index of the second transparent material layer BAL2 maysubstantially be the same.

The residual stress of the first transparent material layer BAL1 and thethird transparent material layer BAL3 may have the same stressproperties. The residual stress of the third transparent material layerBAL3 may be compressive residual stress.

After the third transparent material layer BAL3 is formed, a fourthtransparent material layer BAL4 may be formed on the third transparentmaterial layer BAL3. The fourth transparent material layer BAL4 mayinclude a material that is the same as the first transparent materiallayer BAL1, the second transparent material layer BAL2 and the thirdtransparent material layer BAL3. Therefore, a refractive index of thefourth transparent material layer BAL4 and the refractive index of thethird transparent material layer BAL3 may substantially be the same.

The residual stress of the second transparent material layer BAL2 andthe fourth transparent material layer BAL4 may have the same stressproperties. The residual stress of the fourth transparent material layerBAL4 may be compressive residual stress.

After the fourth transparent material layer BAL4 is formed, a fifthtransparent material layer BAL5 may be formed on the fourth transparentmaterial layer BAL4. The fifth transparent material layer BAL5 mayinclude a material that is the same as the first transparent materiallayer BAL1, the second transparent material layer BAL2, the thirdtransparent material layer BAL3 and the fourth transparent materiallayer BAL4. Therefore, a refractive index of the fifth transparentmaterial layer BAL5 and the refractive index of the fourth transparentmaterial layer BAL4 may substantially be the same.

The residual stress of the first transparent material layer BAL1 and thefifth transparent material layer BAL5 may have the same stressproperties. The residual stress of the fifth transparent material layerBAL5 may be compressive residual stress.

The barrier layer BAL may include transparent material layers BAL1,BAL2, BAL3, BAL4 and BAL5 which include the same material as the basesubstrate SUB. Therefore, light loss may be avoided which may occur dueto the difference in refractive index of the barrier layer BAL and thebase substrate SUB.

As to the barrier layer BAL, the transparent material layers BAL1, BAL2,BAL3, BAL4 and BAL5 having stress properties in which the layers havedifferent residual stress may be alternately stacked. Therefore, theresidual stress applied to the base substrate SUB may be reduced due tothe barrier layer BAL.

Referring to FIG. 6, after the barrier layer is formed, a buffer layerBUL may be formed on the barrier layer BAL. The buffer layer BUL mayinclude the same material as the first to fifth transparent materiallayers BAL1, BAL2, BAL3, BAL4 and BAL5. For example, but withoutlimitation thereto, the buffer layer BUL may include silicon oxynitride(SiON) which is formed through the PECVD process. Accordingly, therefractive index of the buffer layer BUL and the refractive index of thefifth transparent material layer BAL5 may be substantially the same.

After the buffer layer BUL is formed, a thin film transistor may beformed on the buffer layer BUL. The thin film transistor may include asemiconductor active layer SA, a gate electrode GE, a source electrodeSE and a drain electrode DE.

The thin film transistor may be formed as below.

The semiconductor active layer SA may be formed on the buffer layer BUL.The semiconductor active layer SA may include one of amorphous silicon(a-Si), polycrystalline silicone (p-Si) or oxide semiconductor.

A gate insulating layer GI covering the semiconductor active layer SAmay be formed. The gate insulating layer GI may cover the semiconductoractive layer SA and insulate the semiconductor active layer SA and thegate electrode GE.

The gate insulating layer GI may include at least one of silicon oxide(SiOx) or silicon nitride (SiNx). For example, but without limitationthereto, the gate insulating layer GI may include the same material asthe first to fifth transparent material layers BAL1, BAL2, BAL3, BAL4and BAL5, for example, silicon oxynitride (SiON). The gate insulatinglayer GI may have substantially the same refractive index as the bufferlayer BUL. The gate insulating layer GI may be formed by depositing thesilicon oxynitirde (SiON) on the semiconductor active layer SA.

The gate insulating layer GI may include a first layer including siliconoxide (SiOx) disposed on the semiconductor active layer SA and a secondlayer disposed on the first layer and including silicon oxynitridedisposed on the first layer. The gate insulating layer GI may be formedby depositing the second layer which includes silicon oxynitride (SiON)on the first layer after depositing the first layer which includes thesilicon oxide (SiOx) on the semiconductor active layer SA.

The first layer which includes the silicon oxide may have superioradhesive strength with the semiconductor active layer SA. Also,interface stability of the first layer and the semiconductor activelayer SA may be superior. Although damage may occur to the semiconductoractive layer SA when the gate insulating layer GI is formed, the firstlayer may prevent the semiconductor active layer SA from being damagedwhen the gate insulating layer GI is formed.

After the gate insulating layer GI is formed, a conductive metal layermay be formed on the gate insulating layer GI and patterned to form thegate electrode GE. The gate electrode GE may be disposed overlapping thesemiconductor active layer SA. The gate electrode GE may include atleast one of aluminum (Al), aluminum alloy (Al alloy), silver (Ag),tungsten (W), copper (Cu), nickel (Ni), chrome (Cr), molybdenum (Mo),titanium (Ti), platinum (Pt), tantalum (Ta), neodymium (Nd), scandium(Sc) or any alloy thereof.

After the gate electrode GE is formed, an interlayer insulating layerILD may be formed. The interlayer insulating layer ILD may insulate thegate electrode GE and the source electrode and the drain electrode DE.The interlayer insulating layer ILD may include the same material as thefirst to fifth transparent material layers BAL1, BAL2, BAL3, BAL4 andBAL5. The refractive index of the interlayer insulating layer ILD andthe refractive index of the gate insulating layer GI may besubstantially the same.

After the interlayer insulating layer ILD is formed, a part of thesemiconductor active layer SA may be exposed by patterning theinterlayer insulating layer ILD. An area exposed from the semiconductoractive layer SA may be an area coming into contact with the sourceelectrode SE and the drain electrode DE which may be subsequentlyformed.

By forming a conductive layer on the interlayer insulating layer ILD andpatterning it, the source electrode SE and the drain electrode DE may beformed.

Referring to FIG. 7, after the thin film transistor is formed, aprotective layer PSV which covers the thin film transistor may beformed. The protective layer PSV may include at least one layer. Forexample, but without limitation thereto, the protective layer may be anorganic protective layer. The organic protective layer PSV may includeone of acryl, polyimide (PI), polyamide (PA), or benzocyclobutene (BCB).The organic protective layer may be transparent and have fluidity and itmay be a planarizing layer capable of flattening by alleviating a bendor a curve of a structure of a lower portion.

The protective layer PSV may include an inorganic protective layer andan organic protective layer disposed on the inorganic protective layer.The inorganic protective layer may include the same material as thefirst to fifth transparent material layers BAL1, BAL2, BAL3, BAL4 andBAL5. Therefore, the refractive index of the inorganic protective layerand the refractive index of the interlayer insulating layer ILD may besubstantially the same.

After the protective layer PSV is formed, a part of the drain electrodeDE may be exposed by patterning the protective layer PSV.

A display device OLED may be formed, which contacts the drain electrodeDE. The display device OLED may include a first electrode E1 which is atransmissive electrode capable of allowing light to pass through, anorganic layer OL disposed on the first electrode E1 and a secondelectrode E2 which is a reflective electrode disposed on the organiclayer OL and capable of reflecting light.

The display device OLED may be formed as follows.

A transparent conductive oxide layer may be formed on the protectivelayer PSV. The first electrode E1 may be formed by patterning thetransparent conductive oxide layer. The first electrode E1 may come incontact with the drain electrode DE. The transparent conductive oxidelayer may include one of indium tin oxide (ITO), indium zinc oxide(IZO), aluminum zinc oxide (AZO), gallium doped zinc oxide (GZO), zinctin oxide (ZTO), gallium tin oxide (GTO) or fluorine doped tin oxide(FTO).

After the first electrode E1 is formed, a pixel defining layer PDL maybe formed which exposes a part of the first electrode E1 on the firstelectrode E1. The pixel defining layer PDL may be formed by forming anorganic insulating material layer to cover the first electrode E1 andpatterning the organic insulating material layer. The pixel defininglayer PDL may include at least one of polystylene, poly(methylmethacrylate) (PMMA), polyacrylonitrile (PAN), polyamide, polyimide,polyarylether, heterocyclic polymer, parylene, fluorinated polymer,epoxy resin, benzocyclobutene series resin, siloxane series resin orsilane resin.

After the pixel defining layer PDL is formed, an organic layer OL may beformed on the first electrode E1 exposed by the pixel defining layerPDL. The organic layer OL may include at least an emitting layer EML andgenerally have a multi-layer thin film structure. For example, butwithout limitation thereto, the organic layer OL may be formed bysequentially stacking a hole injection layer HIL, a hole transport layerHTL, the emitting layer EML, a hole blocking layer HBL, an electrontransport layer ETL and an electron injection layer EIL.

After the organic layer OL is formed, a second electrode E2 may beformed on the organic layer OL. Accordingly, a thin film transistorsubstrate 110 which includes the base substrate SUB, the barrier layerBAL, the thin film transistor and the display device OLED may be formed.

The second electrode E2 may have a work function that is lower than thefirst electrode E1. The second electrode E2 may include a material withsuperior reflectance. For example, but without limitation thereto, thesecond electrode E2 may include at least one of molybdenum (Mo),tungsten (W), silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt),palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Jr),chrome (Cr), lithium (Li), calcium (Ca) or any alloy thereof.

In embodiments, after the second electrode E2 is formed, a conductivelayer for preventing JR-drop of the second electrode E2 may be formed onthe second electrode E2.

Referring to FIG. 8, after the display device OLED is formed, a sealingmember 120 which isolates the display device OLED from the externalenvironment may be formed. The sealing member 120 may be an opposedsubstrate, for example. The sealing member 120 may be a flexiblesubstrate.

If the sealing member 120 is an opposed substrate, after the sealingmember 120 is disposed to face the thin film transistor substrate 110,the thin film transistor substrate 110 and the sealing member 120 may beattached using a sealant.

Referring to FIG. 9, after the sealing member 120 is formed, the carriersubstrate CS may be removed. For example, but without limitationthereto, the carrier substrate CS may be easily removed by applying heator irradiating a laser beam from a surface of an opposite direction of asurface where the base substrate SUB of the carrier substrate CS isformed.

FIGS. 12 to 14 are simulation graphs for explaining a lighttransmittance in accordance with a structure of a barrier layer disposedon a base substrate.

Referring to FIGS. 12 to 14, the base substrate may include polyimideand have a thickness of approximately 10 μm. Also, the barrier layer maybe disposed on the base substrate.

The barrier layer shown in FIG. 12 may include a silicon oxide layerhaving a thickness of approximately 1500 Å, a silicon nitride layerhaving a thickness of approximately 600 Å, and a silicon nitride layerof approximately 1500 Å. The stacked structure of the base substrate andthe barrier layer shown in FIG. 12 may have light transmittance withrespect to approximately 72.0% red light (660 nm), light transmittancewith respect to approximately 70.1% green light (558 nm), lighttransmittance with respect to approximately 82.8% blue light (428 nm)and approximately 69.6% average light transmittance.

The barrier layer shown in FIG. 13 may be a single silicon oxynitridelayer having a thickness of approximately 5700 Å. The refractive indexof the barrier layer may be approximately 1.7 which is the same as therefractive index of the base substrate. The stacked structure of thebase substrate and the barrier layer shown in FIG. 13 may have lighttransmittance with respect to approximately 86.7% red light (660 nm),light transmittance with respect to approximately 90.3% green light (558nm), light transmittance with respect to approximately 85.1% blue light(428 nm) and approximately 86.9% average light transmittance.

The barrier layer shown in FIG. 14 may include a silicon oxyntride layerhaving a thickness of approximately 1500 Å and whose residual stress iscompressive residual stress, a silicon oxynitirde layer having athickness of approximately 600 Å and whose residual stress is tensileresidual stress, a silicon oxynitride layer having a thickness ofapproximately 1500 Å and whose residual stress is compressive residualstress, a silicon oxynitride layer having a thickness of approximately600 Å and whose residual stress is tensile residual stress and a siliconoxynitride layer having a thickness of approximately 1500 and whoseresidual stress is compressive residual stress. The refractive index ofthe silicon oxynitride layers is approximately 1.7, which is the same asthe refractive index of the base substrate.

The stacked structure of the base substrate and the barrier layer shownin FIG. 14 may have light transmittance with respect to approximately86.7% red light (660 nm), light transmittance with respect toapproximately 90.3% green light (558 nm), light transmittance withrespect to approximately 85.1% blue light (428 nm) and approximately86.9% average light transmittance.

Compared to the light transmittance of the barrier layer in which thesilicon oxide layer and silicon nitride layer are alternately stacked onthe base substrate which includes polyimide, it can be observed that thelight transmittance of the barrier layer where silicon oxynitride layeris disposed on the polyimide base substrate is superior.

Meanwhile, as shown in FIG. 13, the barrier layer of the single layerstructure may have a bigger residual stress than the barrier layer shownin FIG. 14. In the barrier layer shown in FIG. 14, material layers thathave different residual stress properties may be alternately stacked.The material layers may relieve residual stress of each other.Therefore, compared to the barrier layer of single layer structure, thebarrier layer shown in FIG. 14 may maintain a state in which residualstress is relieved.

Embodiments have been disclosed herein, and although specific terms areemployed, they are used and are to be interpreted in a generic anddescriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. A thin film transistor array panel devicecomprising: a base substrate; a barrier layer disposed over the basesubstrate and comprising a plurality of transparent material layers,each of which is substantially transparent; and an array of thin filmtransistors disposed over the barrier layer, wherein the plurality oftransparent material layers comprise first and second transparentmaterial layers immediately neighboring each other without anyintervening transparent material layer therebetween, wherein the firsttransparent material layer has compressive residual stress and thesecond transparent material layer has tensile residual stress.
 2. Thedevice as claimed in claim 1, wherein the barrier layer comprises amulti-layered structure of the transparent material layers arranged suchthat the transparent material layers having compressive residual stressand the transparent material layers having tensile residual stress arealternately stacked.
 3. The device as claimed in claim 2, wherein theplurality of transparent material layers comprises an uppermosttransparent material layer and a lowermost transparent material layerwhich have compressive residual stress.
 4. The device as claimed inclaim 2, wherein each of the transparent material layers comprisessilicon oxynitride (SiON).
 5. The device as claimed in claim 4, furthercomprising a buffer layer disposed between the barrier layer and thethin film transistors, wherein the buffer layer is formed of the samematerial as that of the transparent material layers.
 6. The device asclaimed in claim 4, wherein each thin film transistor comprises asemiconductor active layer, a gate electrode, a source electrode and adrain electrode, wherein the thin film transistor array panel devicefurther comprises a gate insulating layer disposed between thesemiconductor active layer and the gate electrode, wherein the gateinsulating layer is formed of the same material as that of thetransparent material layers.
 7. The device as claimed in claim 6,further comprising an interlayer insulating layer insulating the gateelectrode and the source electrode and the drain electrode, wherein theinterlayer insulating layer is formed of the same material as that ofthe transparent material layers.
 8. The device as claimed in claim 1,wherein a difference between a refractive index of the transparentmaterial layers and a refractive index of the base substrate is withinabout 6%, wherein the thin film transistor array panel device isflexible.
 9. A display panel comprising: the thin film transistor arraypanel device of claim 1; and an array of pixels disposed over the thinfilm transistor array panel device.
 10. The display panel as claimed inclaim 9, wherein the barrier layer comprises a multi-layered structureof the transparent material layers arranged such that the transparentmaterial layers having compressive residual stress and the transparentmaterial layers having tensile residual stress are alternately stacked.11. The display panel as claimed in claim 10, wherein the plurality oftransparent material layers comprises an uppermost transparent materiallayer and a lowermost transparent material layer which have compressiveresidual stress.
 12. The display panel as claimed in claim 9, whereineach of the transparent material layers comprises silicon oxynitride(SiON), wherein the thin film transistor array panel device is flexible.13. The display panel as claimed in claim 12, wherein the thin filmtransistor array panel device further comprises a buffer layer disposedbetween the barrier layer and the thin film transistors, wherein thebuffer layer is formed of the same material as that of the transparentmaterial layers.
 14. The display panel as claimed in claim 12, whereineach thin film transistor comprises a semiconductor active layer, a gateelectrode, a source electrode and a drain electrode, wherein the thinfilm transistor array panel device further comprises a gate insulatinglayer disposed between the semiconductor active layer and the gateelectrode, wherein the gate insulating layer is formed of the samematerial as that of the transparent material layers.
 15. The displaypanel as claimed in claim 14, wherein the thin film transistor arraypanel device further comprises an interlayer insulating layer insulatingthe gate electrode and the source electrode and the drain electrode,wherein the interlayer insulating layer is formed of the same materialas that of the transparent material layers.
 16. The display panel asclaimed in claim 9, wherein a difference between a refractive index ofthe transparent material layers and the refractive index of the basesubstrate is within about 6%.
 17. The display panel as claimed in claim9, further comprising an encapsulating panel disposed over the thin filmtransistor array panel for protecting the pixels from externalsubstances, wherein each pixel comprises a light emitting diode.